In recent years, research and development of organic electronic elements that use organic functional layers formed from organic compounds, is underway in a variety of fields such as organic electroluminescent elements (organic EL elements), and organic solar cells.
Among others, attention is being paid to organic electroluminescent elements (organic EL elements) as image display devices that are capable of emitting high-luminance light based on low-voltage direct current driving, and enable further progress in thickness reduction, weight reduction, and flexibility enhancement.
However, there has been a problem with organic EL elements that when the electrodes are oxidized or organic substances are degenerated due to oxygen, water vapor or the like, deterioration of the performance required as an image display device occurs, such as generation of non-emission spots (dark spots).
Thus, in order to solve such problems, there has been suggested a light emitting element (organic EL element) in which emitted light is extracted through the side of an upper electrode that faces a substrate, the light emitting element having a sealing film formed from a silicon nitride film or the like for the purpose of promoting prevention of the reflection between the sealing film and the upper electrode, and of increasing the luminescence efficiency (see, for example, Patent Document 1).
More specifically, disclosed is a light emitting element formed by sequentially laminating a lower electrode, an organic EL layer, and an upper electrode on a substrate, characterized in that a sealing material having a refractive index that is smaller than 3.5 but larger than the refractive index of air, for example, a sealing film formed from a silicon nitride film, is provided on the surface side of the upper electrode by a CVD method.
Furthermore, there has been suggested a method for manufacturing an organic EL element, which is intended to apply an inorganic sealing layer that has excellent barrier properties and is free of defects over a long time, and to reduce luminescence failure (see, for example, Patent Document 2).
More specifically, disclosed is a method for manufacturing an organic EL element, characterized by including a step of forming a first electrode layer on a substrate; a step of forming an organic luminescent medium layer (organic EL layer) on the first electrode layer; a step of forming a second electrode layer on the organic luminescent medium layer; a step of subjecting the entire substrate to a plasma treatment using a gas containing oxygen atoms (O); a step of forming an inorganic sealing layer formed from silicon nitride, silicon oxide, silicon oxynitride or the like; and a step of performing a plasma treatment on the inorganic sealing layer using a gas containing fluorine atoms (F).
Furthermore, there has been suggested an organic EL device or the like intended to realize high reliability by having a sealing layer that has enhanced durability and is formed from a silicon compound containing nitrogen (see, for example, Patent Document 3).
More specifically, disclosed is an organic EL device or the like formed by sequentially laminating a lower electrode, an organic EL layer, and an upper electrode on a substrate, characterized in that the organic EL device includes, on the surface side of the upper electrode, a sealing layer formed by alternately laminating a first gas barrier layer containing a nitrogen-containing silicon compound and a second gas barrier layer containing an oxide of a nitrogen-containing silicon compound.
Furthermore, there has been suggested a method for manufacturing a gas barrier film that is intended to be used as a substrate for organic EL elements or the like, the method including plasma-treating a polysilazane film so that a gas barrier film that can be easily manufactured can be provided without using a heating treatment or the like (see, for example, Patent Document 4).
More specifically, disclosed is a method for manufacturing a gas barrier film, characterized by forming a polysilazane film on at least one surface of a plastic film, subjecting the polysilazane film to a plasma treatment, and thereby obtaining a gas barrier film, and the method is characterized in that a gas barrier film thus obtained is used as a substrate for an organic EL element.